Characterization of ferrimagnetic and spin wave resonance for frequency selective limiting of iron garnet epitaxial films

High-frequency devices, such as frequency selective limiters utilize magnetic materials such as yttrium iron garnet (YIG). The requirement of low loss to enable low-power limiting requires the material to be of high-quality single crystal. Unfortunately, the low magneto-crystalline anisotropy in YIG requires a bias magnet to generate the necessary field and frequency conditions for spin wave generation at higher frequency operation. Alternatively, the bismuth-substituted rare earth iron garnet (Bi-RIG) (BiGdLu)₃(Fe_1-x Ga_x)₅O₁₂ [1] has been found to show low loss (FMR linewidth ~50 Oe) with high anisotropy field (~2300 Oe), thus possibly avoiding the need for external bias [2]. In this study, we characterize and compare the magnetic properties and power dependences of single-crystal YIG and Bi-RIG grown using liquid phase epitaxy using a vibrating sample magnetometer and a coplanar waveguide configuration to assess dc and microwave magnetic properties for potential use in microwave device integration.

[1] S. B. Qadri et al., Materials Letters 207 (2017) 25–28.
[2] R. Adur et al., IEEE Transactions on Magnetics Vol. 47 No. 6 (2013).